Those snails are a cold water species much like Margarita snails. In reef tank temperatures, their life span will be greatly shortened.
Also, if you could get them from the US, shipping would be expensive as it would have to be Express or overnighted as I doubt they would survive a week in a bag of water.
I should also note that they are not Nassarius snails and don't eat much, if any algae.
A couple links for you:
http://www.reefcentral.com/forums/sh...arius+Obsoleta
http://www.reefcentral.com/forums/se...der=descending